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U.S. Forest Service

Vegetables: Foods from Roots, Stems, Bark, and Leaves

Image banner: cabbages, celery root, radishes, garlic cloves, carrots, and potatoes.

What is a vegetable?

The term vegetable refers to many things. Vegetables may be almost any part of a plant including:

  • Roots
  • Stems
  • Leaves
  • Flowers
  • Bark
  • The entire plant

Vegetables have been divided into major groups:

  1. Edible underground parts, such as roots, tubers, and bulbs.
  2. Edible above ground parts, such as stems, leaves, and flowers.
  3. Edible fruits and seeds, such as usually unripe fruits and seeds.

Edible Underground Parts

Roots, tubers, and bulbs are known as geophytes: plants that have fleshy underground parts that originate from roots, stems, or leaf bases.


Taproots can become swollen and colorful or can remain quite drab but tasty. Examples of common edible taproots include:

  • Carrots,
  • radishes,
  • turnips,
  • beets.

Many native North American tap-rooted plants have served as a main staple for existence. Native Americans from the western portions of North America used one such species, Lewis’ bitterroot. Roots were often collected and dried for winter use. Roots were then boiled and used as a food source when other food sources were scarce. Roots were also used for medicinal purposes including sore throat aid, poison ivy rashes, and heart pain.

This important plant was introduced to Lewis and Clark on their famous expedition in the early 1800s. Specimens were collected on the expedition and were found to resprout many years after being collected and deprived from soil and water. Named in honor of Lewis and its apparent ability to come back to life, this plants scientific name is Lewisia rediviva (rediviva is Latin for “brought back to life”).

Lewisia rediviva. Lewis’ bitterroot (Lewisia rediviva). Photo by Teresa Prendusi.


Tubers are underground plant organs that store important nutrients. Wild tubers and fleshy fruits were among the most important food sources for food gathers prior to agricultural production and are still important to hunter-gather tribes in existence today. Many have considered the potato to be one of the top five plants that have changed the world.

The tuberous potato ranks fourth as a major food staple globally, following only wheat, corn, and rice (grains) respectively. Originating in the Andes, there is evidence that wild potatoes were eaten 13,000 year ago and have been cultivated for at least the last 7,000 years. It is interesting to note that potatoes did not leave the Americas until just a few hundred years ago.

  • The Spanish discovered potatoes being grown in South America in 1500s.
  • Native peoples preserved potatoes by drying them through a process of freezing/thawing into a dry mass of cellulose and starch called chuno.
  • It was not until the 1800s that Ireland began growing potatoes, where the entire country became dependent upon them.
  • The potato blight (1844) caused by a fungus destroyed virtually all Ireland’s potatoes and nearly 1 million people died and another million emigrated, mostly to the U.S. and Canada.
  • Potatoes have been traditionally grown from pieces of the tubers, because the plants are almost always male-sterile.

Two other tubers have been included in the important plants that have changed the world. Manioc (cassava root) and sweet potato are two such plants. Both plant species originated in the new world and have been widely cultivated for their important storage roots. Manioc is a staple food for over 500 million people. Sweet potatoes are often confused with yams. True yams belong to a different genus, Dioscorea, and are grown primarily in Africa.

Potatoes. Potatoes.

White oak tree.Potato plants in flower in the field. Photo by Howard F. Schwartz, Colorado State University,

How the Potato Changed the World

An article from the Smithsonian magazine (November 2011) describes how the potato, brought to Europe from the New World by Spanish explorers, gave rise to modern industrial agriculture. Read the article at…


Bulbs are defined as underground-modified leaf shoots with modified scales or buds. Many of the staple foods we eat are buds. These include onions, garlic, leeks, and shallots.

Onion flowers and inset image of garlic cloves. Wild onions and garlic (right) have bulbs that can be enjoyed as a food source.

Onion flowers and inset image of garlic cloves. Garlic bulbs.

The genus Allium, which includes the onion and its relatives, has been providing important food sources since before recorded time. Humans have made use of the nutrient rich bulbs. Besides providing an aromatic food flavoring, most of the members of the genus have medicinal properties as well. The pungent quality common to the Alliums is tied to the volatile sulfur compounds that are released when the cells of an onion are ruptured.

Sego Lily Bulbs Save Pioneers

The Sego Lily (Calochortus nuttallii) was named the state flower of Utah in 1911 for its beauty, importance as a food source, and because of its role in early Utah history. Early settlers or pioneers to the area were starving due to a large infestation of crop eating crickets. Native Americans had used the bulbs as a food source. Bulbs were roasted, boiled, and made into porridge. Early settlers followed this example and were saved from starvation.

Sego lily. Sego Lily (Calochortus nuttallii). Photo by Kim Pierson.

No More Tears

Basket of a variety of onions.

The volatile sulfur compounds released from onions are water-soluble. Try submerging an onion in water while slicing or chill or freeze an onion before slicing to reduce the effects of the powerful vapors.

Edible Above Ground Parts

Green leaves and stems have been an important part of the human diet for thousands of years. A large portion of the hunter-gatherer’s diet was comprised of uncooked leafy greens. Edible stems were and continue to be important today. Here are some important native edible plants and the parts we consume:

  • Wild asparagus – stem
  • Bracken fern – leaves
  • Stinging nettle – leaves and stems
  • Jerusalem artichoke – tuber and leaves
  • Dogwood – stems (used to clean teeth)
  • Wild onion – all parts

Flowers are Edible?

There are many edible flowers. Some edible flowers are obvious but others are a little harder to detect as truly the flowering structure of a plant. Here are a few favorite flowers or flowering stalks to enjoy:

  • Violets
  • Cauliflower – flowering stalk harvested prior to flowering
  • Capers – often pickled prior to flower opening
  • Cabbage – flowering stalk harvested prior to flowering
  • Dandelion
  • Artichoke
  • Nasturtium
  • Broccoli - flowering stalk harvested prior to flowering
  • Roses

Stinging nettle. Stinging nettle (Urtica dioica) for lunch? Yes, nettles are quite edible. Photo by David. G. Smith, Delaware Wildflowers.

Fun Facts

  • Nettles are edible!
  • Leaves can be cooked into a soup or tea.
  • Hairs on the plant contain formic acid that irritates the skin.
  • Good for arthritis, hay fever, and anemia.

A colorful flower salad on a white plate. This edible flower salad served at a high-end restaurant is a feast for the eye and palate. Photo by Nancy Cotner.